Year Percent 1950 10.1623 1955 10.52468 1960 10.78393 1965 10.64419 1970 10.39718 1975 10.24433 1980 9.19992 1985 8.30074 1990 7.64592 1995 7.88897 2000 9.85438 2005 10.50219 2010 7.58352 2015 4.44921 2020 2.99617 2025 4.56702 2030 5.42134 2035 5.26879 2040 4.82402 2045 4.27487 2050 3.92964 2055 3.88517 2060 4.00776 2065 4.08125 2070 4.0118 2075 3.86274 2080 3.76289 2085 3.79623 2090 3.93692 2095 4.09134 2100 4.17123